[asterisk-bugs] [Asterisk 0014897]: expressions are not working

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=14897 
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Reported By:                johnlange
Assigned To:                
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Project:                    Asterisk
Issue ID:                   14897
Category:                   Functions/func_math
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           1.4.23 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-04-14 14:54 CDT
Last Modified:              2009-04-14 16:03 CDT
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Summary:                    expressions are not working
Description: 
In Asterisk 1.4.23.1, expressions don't seem to be working.

According to the docs (doc/channelvariables.txt),  you should be able to
do this:

exten => 1,2,Set(koko=$[2 * ${lala}])
        

In my system I have this:

exten => i,2,Set(TRIES=$[1 + ${TRIES}])

However, it generates this error:

 WARNING[6389]: ast_expr2.fl:407 ast_yyerror: ast_yyerror():  syntax
error: syntax error, unexpected $end, expecting '-' or '!' or '(' or
'<token>'; Input:
1 + 
    ^

I also reversed it:

exten => i,2,Set(TRIES=$[${TRIES} + 1])

But it still didn't work.

I know this worked in the past so is there something I'm not seeing or
are expressions not working in Asterisk?
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 (0103247) johnlange (reporter) - 2009-04-14 16:03
 http://bugs.digium.com/view.php?id=14897#c103247 
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Ok, so the problem is the variable has to be initialized before it can be
used in an expression. e.g.:

exten => i,1,Set(TRIES=0)

otherwise it evaluates to "" (not "0" as one might expect) in the
expression which is why it generates a syntax error. Strictly speaking this
is probably not a bug unless it used to work differently in a previous
version which I'm not in a position to confirm.

However, it would be nice if uninitialized variables evaluated to the
numeric "0" when used in expressions since it would simplify dialplans
considerably. Also a note in the documentation about that would be a good
idea. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-04-14 16:03 johnlange      Note Added: 0103247                          
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